Add some more unit tests.

Tests/Module/GenerateExportHeader/CMakeLists.txt

...s/Module/GenerateExportHeader/nodeprecated/CMakeLists.txt

...odule/GenerateExportHeader/nodeprecated/CMakeLists.txt.in

Tests/Module/GenerateExportHeader/nodeprecated/src/main.cpp

...odule/GenerateExportHeader/nodeprecated/src/someclass.cpp

.../Module/GenerateExportHeader/nodeprecated/src/someclass.h

Tests/Module/GenerateExportHeader/prefix/CMakeLists.txt

Tests/Module/GenerateExportHeader/prefix/main.cpp

Tests/Module/GenerateExportHeader/prefix/useprefixclass.cpp

Tests/Module/GenerateExportHeader/prefix/useprefixclass.h